<?php
class JSSDK
{
    private $appId;
    private $appSecret;

    public function __construct($appId, $appSecret)
    {
        $this->appId = $appId;
        $this->appSecret = $appSecret;
    }

    public function getSignPackage()
    {
        //获取sha1签名
        $jsapiTicket = $this->getJsApiTicket();

        // 注意 URL 一定要动态获取，不能 hardcode.
        $protocol = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off' || $_SERVER['SERVER_PORT'] == 443) ? "https://" : "http://";
        $url = "$protocol$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";

        $timestamp = time();
        $nonceStr = $this->createNonceStr();

        // 这里参数的顺序要按照 key 值 ASCII 码升序排序
        $string = "jsapi_ticket=$jsapiTicket&noncestr=$nonceStr&timestamp=$timestamp&url=$url";

        $signature = sha1($string);

        $signPackage = array(
            "appId" => $this->appId,
            "nonceStr" => $nonceStr,
            "timestamp" => $timestamp,
            "url" => $url,
            "signature" => $signature,
            "rawString" => $string
        );
        return $signPackage;
    }

    //创建加密字串
    private function createNonceStr($length = 16)
    {
        $chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
        $str = "";
        for ($i = 0; $i < $length; $i++) {
            $str .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
        }
        return $str;
    }

    //获了以ticket
    private function getJsApiTicket()
    {
        // jsapi_ticket 应该全局存储与更新，以下代码以写入到文件中做示例
        $data = json_decode($this->get_php_file("jsapi_ticket.php"));
        if ($data->expire_time < time()) {
            $accessToken = $this->getAccessToken();
            //echo "access_token=" . $accessToken;
            // 如果是企业号用以下 URL 获取 ticket
            //$url = "https://qyapi.weixin.qq.com/cgi-bin/get_jsapi_ticket?access_token=$accessToken";
            $url = "https://api.weixin.qq.com/cgi-bin/ticket/getticket?type=jsapi&access_token=$accessToken";
            $res = json_decode($this->httpGet($url));
            $ticket = $res->ticket;
            if ($ticket) {
                $data->expire_time = time() + 7000;
                $data->jsapi_ticket = $ticket;
                $this->set_php_file("jsapi_ticket.php", json_encode($data));
            }
        } else {
            $ticket = $data->jsapi_ticket;
        }
        return $ticket;
    }

    //获取token
    private function getAccessToken()
    {
        // access_token 应该全局存储与更新，以下代码以写入到文件中做示例
        $data = json_decode($this->get_php_file("access_token.php"));
        if ($data->expire_time < time()) {
            // 如果是企业号用以下URL获取access_token
            //$url = "https://qyapi.weixin.qq.com/cgi-bin/gettoken?corpid=$this->appId&corpsecret=$this->appSecret";
            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=$this->appId&secret=$this->appSecret";
            $res = json_decode($this->httpGet($url));
            //var_dump($this->appId);
            $access_token = $res->access_token;
            if ($access_token) {
                $data->expire_time = time() + 7000;
                $data->access_token = $access_token;
                $this->set_php_file("access_token.php", json_encode($data));
            }
        } else {
            $access_token = $data->access_token;
        }
        return $access_token;
    }

    private function httpGet($url)
    {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($curl, CURLOPT_TIMEOUT, 500);
        // 为保证第三方服务器与微信服务器之间数据传输的安全性，所有微信接口采用https方式调用，必须使用下面2行代码打开ssl安全校验。
        // 如果在部署过程中代码在此处验证失败，请到 http://curl.haxx.se/ca/cacert.pem 下载新的证书判别文件。
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($curl, CURLOPT_URL, $url);
        $res = curl_exec($curl);
        curl_close($curl);

        return $res;
    }

    private function get_php_file($filename)
    {
        return trim(substr(@file_get_contents($_SERVER['DOCUMENT_ROOT'] . '/myapps/' . $filename), 15));
    }

    private function set_php_file($filename, $content)
    {
        $fp = @fopen($_SERVER['DOCUMENT_ROOT'] . '/myapps/' . $filename, "w+");
        fwrite($fp, "<?php exit();?>" . $content);
        fclose($fp);
    }

    /**
     * @Description: 从微信服务器获取图片保存到本地
     * @Author: Yang
     * @param $media_id
     * @return string
     */
    public function getWxImage($media_id)
    {
        try{
        $access_token = $this->getAccessToken();
        $user = $_COOKIE['username'];
        $url = "https://api.weixin.qq.com/cgi-bin/media/get?access_token=" . $access_token . "&media_id=" . $media_id;
        $content = $this->http_get_data($url);
        //创建文件夹
        
        $user_path = $_SERVER['DOCUMENT_ROOT'] .'/myapps/uploadimg/' . $_COOKIE['username'].'/';
        if (!file_exists($user_path)) mkdir ($user_path,0777,true);

        $filename = time() . rand(10, 99) . '.jpg';//文件名
        $filePath = $user_path . $filename;//本地图像绝对路径
        
        file_put_contents($filePath, $content);
        }catch(Exception $exp){
            return "error SAVEFILE";
        }
        return $filename;
    }

    /**
     * @Description: 获取微信服务器上的图片
     * @Author: Yang
     * @param $url
     * @return string
     */
    private function http_get_data($url)
    {
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'GET');
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
        curl_setopt($ch, CURLOPT_URL, $url);
        ob_start();
        curl_exec($ch);
        $return_content = ob_get_contents();
        ob_end_clean();
        return $return_content;
    }
}
?>